Folding a Polymer via Two-Point Interaction with an External Folding Agent: Use of H-Bonding and Charge-Transfer Interactions
作者:Swati De、Debasis Koley、S. Ramakrishnan
DOI:10.1021/ma100189q
日期:2010.4.13
5-dialkoxynaphthalene (DAN)) was coerced into a folded state by an external folding agent that contained an electron-deficient aromatic acceptor (pyromellitic diimide (PDI)) unit. The donor-containing polymer was designed to carry a tertiary amine moiety in the linking segment, which served as an H-bonding site for reinforcing the interaction with the acceptor containing folding agent that also bore a carboxylic
含有富电子芳族供体(1,5-二烷氧基萘(DAN))的聚合物被包含缺电子芳族受体(均苯四甲二酰亚胺(PDI))单元的外部折叠剂强制折叠为折叠状态。含供体的聚合物被设计成在连接链段中带有叔胺部分,该叔胺部分用作H-键位,以增强与还带有羧酸基团的含受体折叠剂的相互作用。羧酸和叔胺的H键相互作用使PDI单元沿着聚合物主链在两个相邻DAN单元之间带动,从而诱导电荷转移(CT)相互作用,进而导致聚合物链形成褶状结构。这种褶状结构形成的证据是从NMR滴定研究以及通过监测其UV可见光谱中的CT谱带获得的。通过改变将PDI受体与羧酸基团连接的链段的长度,我们显示出最有效的折叠剂是具有单个碳间隔基的折叠剂,这从缔合常数的最高值可以明显看出。用丙酸进行的对照实验清楚地证明了额外的CT相互作用对于产生折叠结构的重要性。此外,在存在不同量的折叠剂的情况下进行溶液粘度测量,发现在PDI带有羧酸的情况下链逐渐变硬,而在